Spectroscopic characterization of lanthanide octaethylporphyrin sandwich complexes. Effects of strong. pi. pi. interaction

Journal Article · Wed Apr 25 00:00:00 EDT 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00165a009· OSTI ID:6652249

Duchowski, J K; Bocian, D F ^[1]

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1. Carnegie Mellon Univ., Pittsburgh, PA (USA)

Optical absorption and resonance Raman spectra are reported for the lanthanide sandwich porphyrins, Eu{sup III}(OEP){sub 2}, Nd{sup III}(OEP){sub 2}, and La{sup III}(OEP){sub 2} (OEP = octaethylporphyrin). These complexes contain a single hole in the porphyrin {pi} system and are electronically similar to the Ce{sup IV} sandwich porphyrin cation radical Ce{sup IV}(OEP){sub 2}{sup +}. Variable-temperature (10-300 K) UV-vis and near-infrared (NIR) spectra are obtained for all four single-hole sandwiches. At high resolution and/or at low temperatures, well-resolved fine structure is observed on the intradimer charge-transfer bands (ca. 1,250 nm) of all the complexes. The absorption is dominated by a single Franck-Condon active vibration. This vibration is assigned as a mode, Q{sub AB}, which contains a significant amount of multicenter character and modulates interring separation. Vibronic analysis of the NIR band contours reveals that two system origins, separated by 400-700 cm{sup {minus}1} (depending on the complex), are present. The progressions built off the lower and higher energy origins exhibit spacings of {approximately} 250 and {approximately} 315 cm{sup {minus}1}, respectively.

• OSTI ID: 6652249
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:9; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTRA
CARBOXYLIC ACIDS
COMPLEXES
DATA
DATA ANALYSIS
EUROPIUM COMPLEXES
EXPERIMENTAL DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
LANTHANUM COMPLEXES
MEASURING INSTRUMENTS
MEASURING METHODS
NEODYMIUM COMPLEXES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PORPHYRINS
RAMAN SPECTRA
RARE EARTH COMPLEXES
SPECTRA